NINETIETH ANNUAL MEETING 



OF THE 



Held at Glasgow, July, 1922. 



DISCUSSION ON 

 THE BACTERIOPHAGE (BACTERIOLYSIN). 



I.-THE NATURE OF BACTERIOPHAGE. 



By Dr. F. d'Herelle. 



( From the Pasteur Institute, Paris. ) 



Let us record first, in a few words, the essential facts relating to the present 

 discussion. 



There exist in the intestinal contents of all living beings principles which 

 have the property of dissolving certain bacteria. These principles pass 

 porcelain filters; hence it is possible to separate them from intestinal bacteria. 



Each filtering principle, isolated from intestinal contents of normal indi- 

 viduals, dissolves a certain number of bacterial species, belonging generally to 

 the coli-typhoid-dysentery group. The action, therefore, of these principles is 

 not strictly specific; but belongs, for a given filtrate, to a certain number of 

 microbial species. In convalescents from an infectious disease a principle 

 endowed with an energetic dissolving action on the bacterial species which 

 causes the disease is always met with. 



It is not only towards the intestinal bacteria that these lytic principles 

 exist: for instance, one can isolate from the excreta of convalescents from 

 bubonic plague a principle which dissolves B. pestis; the same phenomenon 

 exists in various animal septicaemias. 



I cannot enter here into an examination of all the facts relating to bacterio- 

 phage,^ facts most of which have been already confirmed by the investigations 

 of other workers. But if the facts themselves have not been contested, it is not 

 so in regard to the hypothesis which I have put forward to explain the nature 

 of the principle which brings about the dissolution of bacteria. 



Reprinted by permission of the British Medical Association from 

 the British Medical Journal, 2 (3216), 289-297, August 19, 1922. 



